Presently, a traditional foldable knife generally comprises a handle and a blade, wherein the blade has an end pivotally connected to an end of the handle. Thus, the blade can be rotated in relation to a pivot portion thereof until the blade is rotated out of the handle for use. Alternatively, the blade also can be rotated into the handle and received therein. When a user wants to use the traditional foldable knife, the user must hold the handle in one hand and draw the blade with the other hand, so as to rotate the blade out of the handle. However, a major disadvantage of the traditional foldable knife is that the user must use both hands to rotate the blade out of the handle. If a particular or emergent condition happens and the user only has one free hand to use, the user cannot speedily use the traditional foldable knife to deal with the particular or emergent condition. For example, when a fisherman is diving and has one hand entangled by a fishnet, the fisherman cannot speedily use the traditional foldable knife to cut the fishnet, resulting in a serious risk to the fisherman's life.
Referring now to FIG. 1, another traditional foldable knife is designed to solve the foregoing problem, wherein the traditional foldable knife comprises a handle 10 and a blade 11. The handle 10 is used to receive the blade 11. The blade 11 has a side formed with a knife edge 111 and an end pivotally connected to a first end of the handle 10 by a pivot 12, so that the blade 11 can be rotated into or out of the handle 10 in relation to the pivot 12. The handle 10 is provided with an elastic member 13 therein. The elastic member 13 has a first end positioned on a portion of the handle 10 adjacent to a second end of the handle 10, while the elastic member 13 has a second end extended to and positioned on a portion of the blade 11 adjacent to the pivot 12. When the blade 11 is completely received in the handle 10, the elastic member 13 biases the blade 11 with a torque to rotate the blade 11 into the handle 10, so that the blade 11 is stably kept in the handle 10. When the blade 11 is forced to be rotated out of the handle 10 to a predetermined angle, the elastic member 13 biases the blade 11 with a torque to rotate the blade 11 out of the handle 10, so that the blade 11 automatically springs out of the handle 10.
In order for the user to conveniently operate the traditional foldable knife, the knife edge 111 of the blade 11 is formed with a protrusion 112 at an end thereof adjacent to the pivot 12. When the blade 11 is completely received in the handle 10, the protrusion 112 will pass through a side of the handle 10 opposite to the blade 11 and protrude out of the handle 10. Hence, a height and a size of the protrusion 112 must be carefully designed so that the user can conveniently press the protrusion 112 in order to force the blade 11 to be rotated out of the handle 10 at least to the predetermined angle, allowing the elastic member 13 to bias the blade 11 with the torque to rotate the blade 11 out of the handle 10, so that the blade 11 can automatically spring out of the handle 10. However, because the blade 11 of the traditional foldable knife must be formed with the protrusion 112 having a considerable height and size, the structure of the protrusion 112 may lower the design aesthetics of the traditional foldable knife. Moreover, the protrusion 112 passes through a back side of the handle 10 where the user needs to hold firmly. Thus, if the user wants to hold the handle 10 in one hand and use the same hand to press the protrusion 112 for the blade 11 to automatically spring out of the handle 10, the user must adjust his or her holding area on the handle 10 considerably to make room for the thumb or the index finger of the same hand to press the protrusion 112. However, it is inconvenient for the user to execute the foregoing operation, and the traditional foldable knife may drop from the hand of the user if the user cannot stably hold the handle 10 with only one hand. If a particular or emergent condition happens and the user only has one free hand to use, the user still cannot use the traditional foldable knife speedily or smoothly to deal with the particular or emergent condition.
In view of the above, designers and manufacturers of foldable knives must design a foldable knife not only to satisfy functional needs but also incorporate a human-based design, so that the foldable knife is enhanced in operational convenience and safety. Therefore, it is important to develop a safe and convenient foldable knife for users to operate easily.
It is therefore tried by the inventor to develop a foldable knife having a switch element to solve the problems with the traditional foldable knife as described above.